Are IL-17 Inhibitors Efficacious in Treating the Nail-DIP Complex in PsA?

In this expert discussion, Katie Springer, PA-C, a rheumatology specialist with Northwestern Medicine in Chicago, Illinois, explores the effectiveness of IL-17 inhibitors in managing the nail-DIP complex in psoriatic arthritis. Nail involvement in PsA is more than just a cosmetic concern—it is strongly linked to DIP joint disease and systemic enthesitis. The nail itself is now understood to be an enthesial site, which means nail disease in psoriasis can be a precursor to psoriatic arthritis. Patients often experience nail changes such as oil spots, pitting, and onycholysis, the latter of which can be misdiagnosed as a fungal infection. The presence of nail psoriasis significantly increases the risk of developing PsA, making it critical to choose a biologic therapy that effectively targets both nail and joint disease.

The SPIRIT H2 trial, a head-to-head comparison of Ixekizumab (IL-17A inhibitor) versus Adalimumab (TNF inhibitor) in biologic-naïve PsA patients, provides valuable insights into the best treatment approach. A post-hoc analysis of the trial included 354 patients with both DIP arthritis and nail involvement, assessing over 1,000 affected finger units. The study revealed that patients treated with Ixekizumab experienced greater resolution of DIP joint tenderness and swelling along with improvements in adjacent nail psoriasis compared to those receiving Adalimumab. These benefits were observed as early as 12 weeks and were sustained through 52 weeks, highlighting the potential superiority of IL-17A inhibition over TNF inhibition for PsA patients with nail disease.

This data underscores the importance of targeted therapy in psoriatic arthritis, particularly in cases where the nail-DIP complex is involved. IL-17 inhibitors like Ixekizumab offer a promising option for patients struggling with both joint inflammation and nail disease.

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